Stay-bolt.



No. 792,863. PATENTED JUNE 20, 1905.

G. s. THOMPSON.

STAY BOLT.

APPLIOATION FILED FBB.15.1905.

2 SHBETS-SHBET 1.

PATBNTED JUNE '20, 1905.

'G. S. THOMPSON.

STAY BOLT.

APPLIOATION FILED FEB.15.1905.

2 SHEETS-SHEET 2.

UNITED STATES Patented June 20, 1905.

PATENT QFFICE.

STAY-BOLT.

SPECIFICATION forming part of Letters Patent No. 792,863, dated June 20,1905.

Application filed February 15,1905. Serial No. 245,646.

To all whom it may concern:

Be it known that I, GEORGE S. THOMPSON, a citizen of the United States,residing at Hockessin, county of Newcastle, and State of Delaware, haveinvented certain new and useful Improvements in Stay-Bolts, of which thefollowing is a specification suflicient to enable others skilled in theart to which the invention appertains to make and use the same.

My improvements relate. to the form and method of construction ofstay-bolts for use in steam-generators, particularly in locomotives,between the outside shell and fire-box shell thereof, and is of theclass wherein each bolt is composed of two parts flexibly connected insuch manner as to allow a certain degree of longitudinal movement uponand with relation to each other, While incapable of independent rotationupon their longitudinal axes.

The invention is designed to afford a maximum of strength for a givensize and thickness of bolt and to prolong its life and usefulness byrelieving the weaker parts of all danger of excessive pressure bydistributing and neutralizing the tension or strain on the partsgenerally both during manufacture and use. It is also designed topreserve the flexibility of the stay-bolt bypreventing the accumulationor lodgment of sediment between the flexible part of the bolt and thesurface opposed thereto, the packing and solidifying of sediment betweenthe parts of flexible stay-bolts having been demonstrated to be a sourceof danger in that it renders the bolt rigid and liable to fracture fromlateral strain, particularly at the point of junction with the plate orshell.

In the accompanyingdrawings, Figure 1 is an elevation of my improvedstay-bolt secured to, say, a boiler-plate and a fire-box plate. Fig. 2isa longitudinal section of the stay-bolt before application to theplates, the section being taken upon plane of line 2 2, Fig. 1. Fig. 3is a longitudinal section of the bolt,.taken upon plane of line 33, Fig.2. Fig. 4 is an elevation of the several parts of which the bolt iscomposed assembled in po sition with relation to each other. Fig. 5 isatransverse section taken upon plane of line 5 5, Fig. 4. Fig. 6 is aview similar to Fig. 4, illustrating the flattening of the side membersof the eye-strap; Fig. 7, a transverse section upon plan e of line 7 7,Fig. 6. Fig. 8 is a side view of the fillet, and Fig. 9 an elevation ofthe inner end of the same. My improved bolt as a whole is formed,essentially, of an eye-head A in one place and a strap .9 and filler f,united integrally to form the eye-bolt B.

The eye-head A is preferably made of malleable cast-steel or drop-forgedsteel formed with a slightly-tapering or conical body or shank a, whichwhen finished is threaded externally and peripherally, as shown in thefirst three figures of the drawings, the rear or outer face or side ofthe head forming the base of the conic frustum, and hence being theportion of greatest diameter. The body or shank a is also preferablyformed with an internal recess a, the side walls of which are formedwith plain surfaces (0 arranged at an angle with relation to each other,so as to afford a hold or purchase for the end of a suitable drivingimplement. An y plural-sided or polygonal form of internal recess a willanswer, and thereby obviate the need of external shoulders for thispurpose, thus insuring a practically flush surface with the outside ofthe sheet 0, which is usually the boilershell by preference. This is ofimportance where the use of asbestos lagging or other covering isdesirable, since it obviates the need of cutting holes in the lagging toaccommodate the heads of the stay-bolts, which are frequently only fourinches apart. It is also an important consideration in locomotives inwhich the wheels extend in close proximity to the outer shell.

The eye a of the head A is oblong, having an approximately semicircularseat a of a diameter equal to that of the cross-section of theconcentric portion of the loop 8 of the strap 8 and an extension a ofgreater area to facilitate the insertion of the strap 8 and also toprevent contact between the strap and the body or shank a of the headduring and after the formation of the eyebolt B, as hereinafter setforth.

In the formation of the eyebolt B a round .rod of wrought-iron or mildsteel of a length equal approximately to twice that of the eyeboltdesired and of a diameter equivalent to the width of the seat a in theeye (4 of the head A is passed through said eye (1, and its ends 8 sbent over parallel to each other and against a central filler f, whichis preferably of like metal and the function of which is not only toform a core or body for the eyebolt, but also to afl'ord a bearing orcontact surface of special construction for engagement with the opposedconcentric surface a of the eye head A. The filler f, with its finishedinner end f, is shown in Figs. 8 and 9 as shaped preparatory to itsincorporation with the ends or side members .9" s of the strap 8 toconstitute the body of the eyebolt Athat is to say, the end f is facedwith two concave surfaces f f 2 of the same radius as that of theopposed concentric surface cf of the eyehead A, against which concentricsurface a they are destined to rest, the said finished end f of thefiller being also formed with a depressed surface or recess f betweenthe concave surfaces f f for the purpose of avoiding central contactwith said concentric surface a of the eyebolt. As a result the bow orbridge of the eye a is practically relieved of all pressure or strainexerted by or upon the bolt A in the direction of the eye-head A, sincethe bearings urfaces f f coincide in position with the sides a a of theeye a when the parts are in alinement, said sides a a constituting,essentially, the piers of the concentric bridge or bow a and beingreinforced by the body of the eyepiece, so that during the swaging,heading, or upsetting of the stub end of the finished bolt in securingit to a plate (Z the strain and impact transmitted to the eye-head A isin the direction of greatest resistance, and the weaker central part ofthe loop is protected and maintained in shape with its fiber unimpaired.Furthermore, by reason of the elongated form of the eye a with itsextension a of greater diameter than its seat a the concentric concavebearing-surfacesf f of the fillerfby their contact with the concentricportion a of the eye-head A also protect the bow or concentric portion 8of the eyebolt B itself, since they hold said concentric portion 5 ofthe strap 8 to its seat a and prevent its contact with the opposed innersurface of the eye head A during the heading or upsetting operation. Bythus preserving the integrity of outline of the concentric portions ofstrap 8 I not only maintain its strength unimpaired, but also preventthe lodgment of sediment between it and the opposed inner surface a ofthe eye-head A, since the uniformly-curved concentric surface s is lessadapted to afford support or lodgment than a battered or irregularsurface, the peripheral surface 8 even when in motion always travelingin the same path and occupying the same position with relation to theopposed stationary surface a of the eye-head A and affording the leastpossible resistance or obstruction to the flow or passage of sedimentbetween said opposed parts, whereas were the peripheral surface s unevenor flattened it would tend to collect sediment between it and theopposed surface a of the eye-head and to compress and harden suchsediment in case of any movement or play of the eyebolt with relation tothe eyehead.

-It will be seen, as before intimated, that the concentric portion 8 ofthe eye of the bolt B is circular in cross-section and of the fulldiameter of the straps as originally applied to the fillerf, thusaffording the maximum degree of strength in the direction of greateststrainnamely, in the longitudinal or axial line of the boltsince in bothform and texture the arch s practically retains the same structure asthat of the rod from which the strap 8 is made. Thus I design to use forthe strap a rod of maximum thickness, afiording a loop or eye thesemicircular diameter of which (see 00 m, Fig. 5) may equal or evenexceed the smaller diameter of the bore or tap a in the plate '0 madefor the reception of the conical eye-head A, in which latter caseobviously the eye of the bolt B could not be passed through saidaperture unless reduced in size laterally. Hence I use a strap ofrelatively large diameter and compress the side members 8 8, adjacent tothe eye of the finished bolt B, by" any suitable means until the greaterdiameter (3 y, Fig. 7) of the eyebolt B is less than that of the smallerdiameter of the tapped hole 0 in the plate 0, so that the said bolt maybe introduced through said aperture. This operation not only reduces thesize of the bolteye externally, but it also sets the fiber of the metalof which this portion of the strap is composed so that resilience andstretch is eliminated, thus insuring an intimate and permanent contactof the concentric bearing-surfaces 1 of the fillerf with the concentricsurface a of the eye-head A when the end members .9" s" of the strap 8are Welded to the filler f, and thereby obviating all looseness or playlongitudinally between the head A and bolt B. Practically, however, toall intents and purposes the eyebolt or loop is of a size and strengthequivalent to that afforded by the full diameter of the bar or rod ofwhich the strap is made, since the compression of the side members 8 8,while it alters their shape in cross-section from a circular toapproximately that of an oval, does not essentially reduce their area incross-section, the elongation being slight and being taken up andcompensated for in the welding of the said side members 8 s to thefiller; hence the avoidance of subsequent stretch and the maintenance ofthe maximum degree of resistance against strain or pressure. Thisrelatively high degree of strength and tenacity in the bolt B is alsocontributed to largely by the continuity of fiber maintained in thestrap by forming it of a single piece or rod of metal bent over upon andwelded 'to the filler f, the strap 8 extending at either extremity tothe stub end of the bolt, so as to be included in the upsetting orheading process by which this end of the bolt is secured to the plate d,as illustrated in Fig. 1. Thus the strain or pressure in use isuniformly distributed throughout the bolt, the weld extending on bothsides of the filler from eye to stub end and there being no relativelyweaker portion, as where an end of a I loop drawn out from the body onone side is welded to a small area on the other side of the bolt-body,as heretofore, in which case the strength of the weld represents theavailable maximum strength of the stay-bolt. After welding and shapingthe body of the bolt B its stub end is formed with the screw-thread Z)for engagement with a thread 66', tapped in the plate 61. The bolt B ispreferably made longer than actually necessary, so as to facilitate theintroduction of the said stub end through the tap 0' into the tap 0Z2,the superfluous portion of the stub end being chiseled off after theeye-head has been driven home and preparatory to the upsettingoperation.

What I claim as my invention, and desire to secure by Letters Patent, is

1. A two-part stay-bolt consisting of an eyehead formed with a taperedbody portion which is threaded, and an eyebolt, the parts being coupledtogether by the interlocking of their eye-loops for the purposedescribed.

2. Atwo-partstay-boltconsistingof an eyehead formed with a semicircularseat in its eye and with an external surface concentric to said seat,and an eyebolt coupled to said eye-head and formed with bearing-surfaceswhich engage with said concentric surface on the eyehead, the bolt beingrecessed centrally between said bearing-su rfaces for the purpose setforth.

3. Atwo-part stay-bolt consisting of an eyehead formed with asemicircular seat in its eye and with an external surface concentric tosaid seat, and an eyebolt coupled to said eye-head and formed withbearing-surfaces which engage with said concentric surface on theeyehead,the bolt being recessed centrally between said bearing-surfacesfor the purpose set forth.

4. A two-part bolt consisting of an eye-head formed with a semicircularseat in its eye with an extension of the eye of larger diameter than thesaid seat and with an external surface concentric to said seat, and aneyebolt coupled to said eye-head and formed with bearing-surfaces whichengage with said concentric surface on the eye-head, the bolt beingrecessed centrally between said bearing-surfaces for the purpose setforth.

5. A two-part stay-bolt consisting of an eyehead and an eyebolt coupledtherewith, said eyebolt being formed of a central filler and of a strapwelded thereto and extending the full length of the bolt on oppositesides of the filler, for the purpose set forth.

6. A two-part stay-bolt consisting of an eyehead and a bolt coupledthereto, said eyebolt being formed of a central filler and of a straplooped into the eye in the said eye-head, and having its ends welded tothe filler for the purpose described.-

7 A two-part stay-bolt consisting of an eyehead and an eyebolt coupledtherewith, said eyebolt being formed of a central filler and of a strapwelded thereto, the side members of the strap being flattened beyond thebend of the loop or eye for the purpose set forth.

8. A two-part stay-bolt consisting of an eyehead formed with a taperedbody portion which is threaded, said threaded body having a centralrecess the side walls of which are adapted to engage with a drivingimplement, and an eyebolt, the parts being coupled together by theinterlocking of their eye-loops for the purpose set forth.

GEORGE S. THOMPSON.

Witnesses:

CORNELIUS ECKHARDT, JOHN H. ONTRICH.

